Improvement in hydraulic presses



duurt time @anni @tithe IMPROVEMENT IN HYDRAULIC PRESSES.

The Schedule referred -to in these Letters Patent and making part. ofthe same.

To all'whom it ma/ z/ concern:

Be it known that I, THoMhs HARBOTTLE, of Brooklyn, in the county ofKings, and State of New York, have invented a new and useful Improvementin Valve- Gear for Hydraulic Presses; and I do hereby declare that thefollowing is a full, clear, and exact description thereof, which willenable others skilled in the art to make and use the same, referencebeing had to the accompanying drawings, forming part of thisspecification, in whichn Figure 1 is a longitudinal vertical sectionthrough the block, which contains thc valves and passages leading to andfrom the same, the section being taken through the line a; x, fig. 2.

Figure 2 is an end view of the block, showing a side view of one of therelief-valve levers.

Similar letters of reference indicate like parts.

The object of this invention is to obtain a simple and effectiveautomatic valve-gear for hydraulic presses,

whereby the check-valves will close instantly'and automatically at theend of each stroke of the pump, and each of the relief-valves will dulyperform its respective functions without aliecting the operation of l`the other check-valves or relief-valves connected with the same pump,-but different presses.

.-In the valve-gear of hydraulic presses generally, the great pressurerequired necessitates the use of a solid metal block, which is bored outto receive solid valves andfto afford seats for` the same, and is alsobored out to obtain passages'of small calibre for the oil or fluid usedto pass through to the valves, and to the pipes leading to the pumps andpresses. f

And my invention consists in the relative arrange;

. ment of such valves and passages, and also in the employment ofindependent or automatic check-valves, moving freely within chambers inthe said block, and also in the employment of relief or safetyvalves,arranged within the said block, in such relation to the check-valves andpassages communicating therewith, as to operate in the l,mannerhereinafter set forth; and

the present invention may be considered as an improvement on thevalve-gear of hydraulic presses generally, as the principal advantagesobtained thereby arei First, the maintenance of pressure in the rams ofone or more of a series of presses connected -with the same pump or setof pumps.

Second, the simple and expeditious character of the manipulationrequired at the hand of the attendant in changing the connection of thepump from one press to the next. l

And, finally, the absence of that vigilant attention on the part of theoperator, which, with some Aof the presses hitherto provided, isrequired to prevent injury and breakage, and with others to obtain themost economical working of the presses.

I am thereby enabled to operate a number of presses by the same pump orpair of pumps, without loss of time in waiting for any one of the ramsto discharge before another is filled, or without requiring more thanone attendant for the pump and valves otl a number |of the presses. A

My invention will be more clearly understood by reference to thedrawings, in which A is a metallic block, having a horzontaltransversepassage, I, which communicates with the pump or pumps, forcing fluid tothe rams of the presses.

In the drawings, the valves and passages are provided for two pressesonly, which number is, however, suiiicient to illustrate the invention;but itv will be observed that the chief value of the same lies in thcfact that a number of presses may be easily and economically 'workedfromone and the same pump or set of pumps. A v

G 'G are two independent check-valves, having a slight lift in theirrespective chambers, which latter are bored out of the block, as shown.

The reduced ends of these valves are formed to fit against conicalseats, f j, surrounding the short passages h, leading from the mainpump-passage I, and these valves, when seated, shut orf the 110W of duidto or from the passage a, leading to the rams of the presses l'Theconstruction, arrangement,-and function being the same for each pair ofvalves and their respective passages, one pair only will be describedin`detail.

The check-valveGis a solid cylindrical mass bf metal, and is formed withfillets d d, which serve as guides to keep the valve in the axis of itschamber i l the passage a, leading to the ram-chamber of the ress. v pIn practice, a small copper pipe, leading to the ramchamber of thepress, is 'connected with the external orifice of this passage a, While,in a similar mannera pipe leads from the passage I to vthe pump orpumps, andlalso a pipe leads from the external orifice of the passageb', which latter is acontinuation ofthe passage t from above the seatofthe relief-valve O to the tank from whence the pump draws the iluid,which it delivers into the passage I..

,The passage a opens into the passage b, between v the check-valve Grand the relief-valve O, which latter is a solid metal cylinder, formedwith a reduced lower end, g, around which the iinid Hows to the externalpassage b', leading from the bore in which the reliefvalve works.

The said reduced end, g, is formed with a conical base, which fitslightly against the seat e e, surrounding the vertical part of thepassage b.

In order to limit the play of the check-valve G, and also to close itsbore or chamber, the latter is iitted with a plug or stop, B,which'isformed with a reduced part, B', which projects into the bore orchamber of l the check-valve, and is made tight therein by leathercup-packin g.

yThis plug must be adjustable up or down, so that the part B may bebrought to bear forcibly against the check-valve, in order to hold itimmovably to its f seat when the duid is to be shut on" from the press,or to remove the said part B a short distance 'om the check-valve, inorder to allow the valve to lift and seat with each stroke of the pump.

The simplest and best method of operating the stopplug B is by means ofa screw-thread cut on the said plug, and working in a hollow kthread cntdirectly iu the block, or in a nut tapped into the-block, as shown,which latter method is preferable, for the purpose of packing the partB.

In practice, the part bearing the thread should be enlarged, in order toaiord a thread of suitable strength and pitch.

In the drawing, the block, valves, and passages are shown in the full oractual site as employed in practice, and square-threaded screws, of'small pitch, as therein shown, are also of the requisite relativedimensions'.

yThese plugs are formed with square heads, H, affordin g attachment forlever-handles, by means of which the attendant operates the stop-plugs.

D are the Weighted levers, pivoted to lugs E, and

resting on the ends of the relief-valves, which project from theirbores, above the upper face of the block A, as shown.

These levers are weighted, to. obtain the desired pressure per squareinch in the pipes, passages, and ram-chamber, and Awhen the pressure inthe ramchamber exceeds this predetermined pressure, the reliefvalveswill be raised, thus permitting a slight escape of the uid, through thepassage b', until the valve again seats.

In the operation of this valve-gear, the water or oil (the latter beinggenerally used) is forced by the pump into the passage l.

The check-valves being free to work, consequently all the presses of theseries will be operated simultafv neously.

When all the presses are up, that is `to say, when the matter in them iscompressed to the utmost degrec required, the presses are tobe lowered.

The attendant now screws down the stop-plug of one of the cheek-valves;for example, the first ofthe series, which seats the valves rmly, thuspreventing any oil from passing either to or from the passage I, throughthat valve. l f

The relief valve belonging to the press is then raised by the attendant,and the oil discharged from the ramchamber of the first press back,throughl the passage b to the pump tank.

The stop-plug is then raised again, and the press operated as before,while the attendant proceeds to perform the same operation successivelyon the'valves of each press of the series, and returning again to the4lrst press, which by that time had been brought up and remained in thatcondition, compressing the matter placed therein.

Should the pressure exceed the degree required, the same will beequalized throughout the series of presses (except the one beingdischarged) by the action of any one of the relief-valves; and hereanother advantage obtains incidentally, for it frequently occurs in thepractide that safety-valves at the pump-gear of hydraulic presses, asheretofore made, from some cause not well understood, (generallyconsidered to be the collection of air under the safety-valve,) refuseto lift at the presses for which they are weighted, thereby' producingbreakage oi' some part of the mechanism.

By my invention, however,.ii`.only one of the reliefvalves operates atthe proper pressure, the excess of pressure in the passage I will iindvent by the way of the check-valve and relief-valve of that particularpressure, lthereby equalizing the pressure at all the valves andpassages of the presses which are up.

Another advantageous-mature resulting from my inventionl is due to thearrangement of the reliefvalves in 'the passages b b', which lattercommunicate with each other, and with the press-passage a, and

the check-valve chamber, above the seat of the latter valve, whereby therelief-valve serves also `as a safetyvalve, but is Free from the violentjumping action heretofore experienced in such valves, from theirintimate connection with the pumps; but in the present arrangement, thepulsation or shock of the oil is first felt and softened by thecheck-valve, and after passing it does not act upon the relief-valvesuddenly and harshly, having the continuous medium oi oil extending tothe ram-chamber to receive and diiuse the shock up to the very instantwhen the relief-valve lifts automatically from excessive pressure.

In the most approved combination of valves for hydraulic presseshitherto employed was that of myself and another, wherein twoscrew-valves geared tightly, so as to seat and lift`reversely.

passage from the press to the tank, and the other closing the passagefrom the pump to the press, a cock in the pump-passage being employedvto shut oi the communication with the pump, While the geared valves werebeing shifted.

Where a series of these were used, the attendant was compelled to chargethem rapidly and correctly, to avoid loss of pressure or. breakage; butwith the present invention, it -ishardly ppssible for breakage or lossof pressure to occur through neglect on the part of the attendant. l

When any hydraulic presses are employedl in eX- pressing liquid residentin matter, (as in expressing linse'ed-oil and the like,) which requiresgreat pressure, the most effective or productive moment of pressure isthe terminal pressure, that is to say, the highest degreev of pressurewhich isobtained and maintained on the matter when the presses are up totheir full extent, whereby the throbbing action of the pump-Huid is madeto act on the matter with its full ei'ect.

Now, this highest degree of pressure willbe lost in charging the valves,unless the same are check-valves, which retain the pressure in mannerdescribed, and at the same time permit the pumps to continue workingwithout breakage.

By the employment of check-valves, the pressure may be retained in anyone or all of the ram-chambers, without danger or detriment, for anydesired time, and the attendant is not required to be constantly presentand vigilant in order to insure the proper working of the presses.

It will be observed that one oi' the-important features of my inventionis' the stop-plug B' B, and, as shown in the drawing, is a screw-plug,to be operated by a hand-lever or Wrench; but I desire to be understoodas not limiting my invention to ascrew-stop plug, or even`a screw-stop,for this feature is subject to two legitimate modifications, of whichthe first is to dispense with the screw-threads, and form the part Bcylindrical, and fit it air-tight (or pack it) into the bore, allowingthe end to project above the block, as do the relief-valves O, a leverand Weight being employed, as in the latter valves'.

This modification would 'be desirable when the presses were remote fromthe pumps; or the part B, projecting upward as before,.might be actedupon by means of a set-screw workingv in a nut formed in a yoke or plateof metal affixed to the upper surface of the blockA, and arching overthe projecting end of such closely-fitting stop-plug, or an analogousprojection from and continuous with the check-valve itself.

In both of these modifications, the adj ustability of the check-valvewould be permitted.

In the case of the weighted lever, the same would be raised by a ropeand pulley, leading to the attendants locality. v

In practice, a cup-packing of leather is used, which surrounds. the partB', and is held inr place by the nuts of the screw-stops, as shown.

They were operated by hand, one valve closing theI I am aware of theexistence of the patent, number 79,949, July V14:, 1868, to W. P.Callahan, and I claim nothing that is therein embraced; but having thusdescribed my invention,

What I'olaim as new, and desire to secure by Lef;-V

ters Patent, isn The arrangement of the passage I, passages h,check-valves G, adjustable stops B' B', passages b ba, and therelief-valves C, as herein described, whereby each press is relievedindependently, the pulsation of the liquid upon the relief-valvesreduced, and one block provided for a number of presses, for the purposespecified. A

The above specification of my invention, signed by me, this 29th day ofOctober, 1868.

THOS. HARBOTTLE.

Witnesses:

F. BLOOKLEY, E. G. COLLINS.

